Parkinson disease (PD) is a complex disorder with motor, cognitive, and behavioral dysfunctions that change over time. The methods to study PD have also become ijiore complex, including the study of biomarkers, genetics, and postmortem-dependent neurobiology. Thus, a successful Clinical Core must not only characterize the motor, cognitive, and behavioral function in PD subjects over time, but also concomitantly carefully collect biological fluids during that same timeframe, and obtain postmortem material from these well-characterized subjects. The primary goal of the Clinical Core will be to support the Pacific Northwest Udall Center (PANUC) Projects through longitudinal characterization of PD subjects and generation of biologic samples from these subjects. To accomplish this goal two PD subject samples will be established. The "community" sample (CS) will be a larger sample evaluated by Clinical Core study personnel at local movement disorder clinics, or at their homes, twice during the five year Center funding cycle. This sample will generate the large number of blood samples, with clinical characterization, needed for the biomarker and genetic projects. The CS will also be the source of subjects for the "annual" sample (AS). The AS will be a smaller subject sample selected for clinical characteristics on screening (e.g., cognitive subtypes such as cognitive impairment without dementia). AS subjects will be evaluated annually at the study site and will have more detailed clinical characterization. In addition, these subjects will be recruited for lumbar punctures to supply CSF for biomarker studies, and for autopsy. The Clinical Core will, therefore, develop PD subject samples with detailed clinical characterization, and collect biological samples from the subjects, to support Projects 2 and 3 in PANUC as well as closely aligned studies. Clinical data, DNA, and biofluids from control individuals will be obtained through the same protocols at each sites'respective NIH-funded AD Center. These unique and integrated data and samples from longitudinally evaluated PD subjects will be an invaluable resource for future studies by PANUC investigators, and for other investigators from within and outside the participating institutions. RELEVANCE (See instructions): Parkinson's Disease (PD) is a progressive disease of the brain that currently affects over a million Americans. We now know that in addition to the movement problems commonly associated with PD this disease eventually also affects a persons thinking or cognitive abilities. This study will improve our understanding of what causes PD-associated cognitive decline, with the long-term objective of developing better treatments for this disabling facet of PD.